Means for deaerating and cooling the driving medium of hydraulic gears.



H. LENTZ.

MEANS FOR DEAERATING AND COOLING THE DRIVING MEDIUM 0F HYDRAULIC GEARS.

APPLICATION FILED OCT-28,1?I3- I 1,164,1U5 R I Q. I Patented Doc. 14,1915.

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llNltlllD b TATd PATENT @FFICE HUGO LENTZ, 0F HALENSEE, NEAR BERLIN,GERMANY.

MEANS FOR DEAERATING AND COOLING THE DRIVING MEDIUM 0]? HYDRAULIC GEARS.

Application filed October 28, 1913.

To all whom it may concern:

Be it known that I, HUGO Lnx'rz, a citizen of the German Empire, andresiding at Halensee, near Berlin, Germany, have invented certain ;newand useful Improvements in Means for Deaerating and Cooling the DrivingMedium of Hydraulic Gears, of which the following is a specification.

My invention relates to apparatus for cooling and removing the air fromthe driving medium of hydraulic gears.

It has already been attempted to remove the air from the driving mediumof hydraulic gears by connecting the suction chamber of the pumps by twopipes with an elevated tank, the oil mixed with air being contained inthe one pipe and the oil free from air in the other pipe, so that inconsequence of the excess weight of the column of oil free from air theoil circulates between the suction chamber of the pump and the tank. As,in this apparatus, the circulation of the oil depends solely on thesmall difference in weight of the two columns of liquid, the circulationof oil can only be exceedingly weak. Therefore with this apparatus it isnot possible to remove sutlicient air, and still less simultaneously tocool the driving medium, because only an exceedingly small part of theentire operative quantity of oil is conveyed into the tank; the greaterpart of the oil remains, on the contrary, uncooled inside the gear,Particularly, such an apparatus cannot be employed for motor-cars andthe like, because in such vehicles there are no appreciable differencesof level at all at disposal and, further, the jerks caused during travelare so severe that they entirely negative any such action due todifference of height. a

A -orimary object of my invention is ellectively to remove the air fromthe fluid medium and also to cool the latter in an improved manner.

To this end, li cause powerful circulation of oil by connecting by meansof a bypass pipe having a tank connected therein two chambers in whichdifferent pressures exist, namely the suction chamber, and an exhaustchamber which is separated therefrom by a regulating member and in whicha pressure is produced owing to the fluid being dammed back. The entirechamber of the gear is subdivided into three cham- -i bers, namely, thesuction chamber of the pumps, the delivery chamber which suppliesSpecification of Letters Patent.

Patented Dec. 14, EH5.

Serial No. 797,846.

the working liquid from the pumps to the motors and in which the workingpressure for the time being exists, and an exhaust chamber arrangeddirectly behind the outlets of the motor and separated from the suctionchamber by a regulating member, valve, or the like. In the exhaustchamber a pressure is produced on the one hand by the resistance of thesaid regulating member, and, on the other hand, by the conveying actionofthe motors, while the ordinary suction pressure exists in the suctionchamber of the pumps. Now instead of connecting, as heretofore, twoplaces at different elevations in one and the same chamber (2'. c. thesuction chamber) which receives the driving liquid relieved of pressure,I connect together two difierent chambers, namely the suction chamber,which receives the discharged driving liquid relieved of pressure, andthe exhaust chamber which receives the discharged driving liquid underpressure, and consequently a more powerful circulation of the liquid isproduced in the by-pass pipe, so that all the driving liquid has the airremoved from it and is cooled in a short time. It is not necessary, asin apparatus known heretofore, to arrange the tank high above the gear,for the purpose of producing a height of fluid premure produced solelyby the difierence of weight, but the tankmust be located only a littleor not at all above the gear, because the difference of pressure whichis produced always brings about a powerful circulation of oilinclependently of the elevation of the tank.

One illustrative embodiment of the invention is represented by way ofexample in the accompanying drawing, wherein Figure 1 is a longitudinalsection through hydraulic gear, and Fig. 2 is a section through thehydraulic pumps of the gear taken on the line ill-ll in Fig. 1.

Referring to the drawing, the gear comprises the twin pump 7; driven byany prime mover and. connected by the delivery cham-- her (7 to thehydraulic motors c. from which the fluid passes into an exhaust chamber6 which is separated by the member 7, used for example, for reversing,from the suction :lxr-t 0 connected directly to the set of pumps Z. iby-pass pipe 7:, 2' branches oil from t exhaust chamber 6 and thesuction duct a. mto which pipe is connected a tank 8 which ma v be inconnection with the atmosphere. Now as this reversing member 7,

which must be provided, has an ap reciable unavoidable resistance, inconsequence of the conveying action of the motors 0 a pressure isproduced in the exhaust chamber 0 which is'far higher than the pressurein the suction duct 0. Owing to this difierence of pressure a powerfulcirculation of the oil is caused in the direction of the arrows shown inFig. 1, so that the particles of air separate out in the tank and theoil can effectively cool. The circulation of the driving medium isregulated by the valve f and the damper or throttle valve 9. Preferablythe one branch pipe 2' branching ofl from the suction duct 0 opensdirectly in front of the reversing valve 7, while the second branch pipe70 branched off from the exhaust chamber 6 opens at the highest point ofthe gear close behind the exhaust port of the motors 0.

The apparatus operates as 'follows:- When the gear is stationary all thethree said chambers are at the same pressure. WVhen the gear is driven adifference of pressure is produced between the two outlets m and nbecause the one outlet m opens directly into the suction duct of thepump where the low suction pressure exists, while the other outlet 11.is located behind the valve 7 in the exhaust chamber e at the highestpoint of the gear where the hydraulic pressure is far greater thanin thesuction duct, as it has to overcome, in addition, the frictionalresistance up to the valve and the resistances in the valve itself. Inconsequence of this difference of pressure a part of the driving mediumis constantly powerfully circulated in the by-pass pipe; it issues outof the highest part of the gear, takes with it the air there collectedand flows through the branch pipe is into the tank, here allows the airto escape into the open and is then sucked free from air and cooledthrough the branch pipe 27 into the gear.

The apparatus can be readily employed for filling the gear with oil. Itis only neces sary to fill the tank with oil and to slowly start themotor and the pump of the gear. The oil is then sucked into the suctionchamber, while the air can escape out of the exhaust'chamber through thepipe is until the gear is filled with oil.

I claim 1. The combination with hydraulic gear comprising a suctionchamber, an exhaust chamber in direct communication with the suctionchamber and a valve between the chambers, of an auxiliary circulatingsystem comprising a pipe opening at one end into the suction chamber andat the other end into the exhaust chamber, and a tank connected intosaid pipe.

2. The combination with hydraulic gear comprising a casing containing asuction chamber and an exhaust chamber in communication with the suctionchamber, a pump connected to the suction chamber, a motor connected tothe exhaust chamber and reversing valves between the suction chamber andthe exhaust chamber, of an auxiliary circulating system comprising aby-pass pipe opening at one end into the suction chamber and at theother end into the exhaust chamber, and a tank connected into said pipe.

In testimony whereof, I aflix my signature in the presence of twowitnesses.

HUGO LENTZ.

W'itnesses:

HENRY HASPER, WOLDEMAR HAUPT.

